1agt | pdb_00001agt
SOLUTION STRUCTURE OF THE POTASSIUM CHANNEL INHIBITOR AGITOXIN 2: CALIPER FOR PROBING CHANNEL GEOMETRY
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Overview
The structure of the potassium channel blocker agitoxin 2 was solved by, solution NMR methods. The structure consists of a triple-stranded, antiparallel beta-sheet and a single helix covering one face of the, beta-sheet. The cysteine side chains connecting the beta-sheet and the, helix form the core of the molecule. One edge of the beta-sheet and the, adjacent face of the helix form the interface with the Shaker K+ channel., The fold of agitoxin is homologous to the previously determined folds of, scorpion venom toxins. However, agitoxin 2 differs significantly from the, other channel blockers in the specificity of its interactions. This study, was thus focused on a precise characterization of the surface residues at, the face of the protein interacting with the Shaker K+ channel. The rigid, toxin molecule can be used to estimate dimensions of the potassium, channel. Surface-exposed residues, Arg24, Lys27, and Arg31 of the, beta-sheet, have been identified from mutagenesis studies as functionally, important for blocking the Shaker K+ channel. The sequential and spatial, locations of Arg24 and Arg31 are not conserved among the homologous, toxins. Knowledge on the details of the channel-binding sites of agitoxin, 2 formed a basis for site-directed mutagenesis studies of the toxin and, the K+ channel sequences. Observed interactions between mutated toxin and, channel are being used to elucidate the channel structure and mechanisms, of channel-toxin interactions.
About this Structure
1AGT is a Single protein structure of sequence from Leiurus quinquestriatus hebraeus. Full crystallographic information is available from OCA.
Reference
Solution structure of the potassium channel inhibitor agitoxin 2: caliper for probing channel geometry., Krezel AM, Kasibhatla C, Hidalgo P, MacKinnon R, Wagner G, Protein Sci. 1995 Aug;4(8):1478-89. PMID:8520473
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